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Why does the pKa - pKb relationship hold when Kw holds for the autoionization of water? |
Is standard change in activation Gibbs free energy indepedent of pressure? |
Can someone tell me how many structural isomers exist for 1,2-dimethyl cyclohexane? My teacher said there is one structural isomer but I believe there aren't any because there is no other way to define the structure of the above compound such that they have the same molecular formula but a different structural formula.... |
I'm trying to react succinic anhydride with a decyl alcohol to produce mono-decyl succinate. Literature and Google searches suggest that the monoesterification should proceed without catalyst. However I'm failing to get the reactions going. Reactions were in reflux, $\pu{80-140 ^\circ C}$ at $\pu{1 atm}$.
Any sugges... |
How can chlorine be 'only' the third-most electronegative element yet have the highest electron affinity? |
The reactants were treated with $\ce{NaOH} $. How the product here obtained. Can you show me the reaction mechanism for this. I found this is somewhat Retro Aldol Condensation. But how?[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/XEHDm.png |
I try to understand, from the *electromagnetic side only*, how the molecule could be more stable than each atom, and concluded that it could not. Where is my mistake?
Here is an illustration :
By using a ruler in order to have an "example" of numerical values, we conclude, by taking the numerical values of distan... |
[![OP's carbon numbering][1]][1]
This is how I did the numbering for this question. Taking all the functional groups in principal chain but my sir did this way.
[![OP's authoritative answer][2]][2]
[1]: https://i.stack.imgur.com/QjAjW.jpg
[2]: https://i.stack.imgur.com/6DoTp.jpg
In my teachers answ... |
Before I start of this question, Ι want to make it clear that I know that hybridization, like pretty much all of chemical bonding, are just made up to qualitatively rationalize observations. I know that theres no actual orbital overlapping, resonance, excitation.... and what not, and the only real things governing "bon... |
Here is what I think I know: The entropy of dissolution reactions increases as methylene groups are added (i.e. butanol has higher entropy of dissolution than propanol). Also, acyclic saturated hydrocarbons become more hydrophobic as the number of methylene groups increases.
Here is where I get confused:
Larger ... |
Why is a triangular cavity created during wire-cutting of an organic gel? |
I discussed the following today.
1. If adding an iodine crystal to a Grignard to make the reaction go. will this tiny crystal force some of the metal or reagent to be used up. ergo, therefore, there is a lower yield (I know it is microscopic change, this is not the question)
It is more about if it takes some of ... |
I am looking for a liquid that floats on water that will prevent the water from freezing (or at least slow it down). The application would be a small area (less than a square foot). It has to be non-toxic as I do not want to harm any critters. Thoughts??? |
What is non toxic to fish, has a low freezing point, and floats on water? |
[Liquid nitrogen][1] seems to be attracting a bit of attention at the moment as a medium of energy storage, both for electricity grid applications and for transport.
For example, [Highview (via the Internet Archive)][2] are doing round-trip electricity storage via liquid nitrogen.
![enter image description here]... |
I discussed the following today.
1. If adding an iodine crystal to a Grignard to make the reaction go. will this tiny crystal force some of the metal or reagent to be used up. ergo, therefore, there is a lower yield (I know it is microscopic change, this is not the question)
It is more about if it takes some of ... |
Before I start of this question, Ι want to make it clear that I know that hybridization, like pretty much all of chemical bonding, are just made up to qualitatively rationalize observations. I know that theres no actual orbital overlapping, resonance, excitation.... and what not, and the only real things governing "bon... |
I discussed the following today.
1. If adding an iodine crystal to a Grignard to make the reaction go. will this tiny crystal force some of the metal or reagent to be used up. ergo, therefore, there is a lower yield (I know it is microscopic change, this is not the question)
It is more about if it takes some of ... |
I do a lot of short term ocean field deployments where system electronics are self contained in a submersible enclosure. A new project I'm working on requires a long term deployment in the deep ocean. Therefore, once the enclosure is deployed, I can not just go recover the instrument if something fails. I've spoken to ... |
There are oils sold for swimming pools to slow or stop evaporative cooling . That would be a problem for air breathers like mosquito larva. I don't know anything about it because I went with 1" thick Styrofoam panels. That is what I currently have on my pond ( 10' X 5 '), works very well .I cheat a little and have 150 ... |
I don't know if there would actually be oxygen and nitrogen snow. I would think under those circumstances, there might be carbon dioxide snow, but the rest of the atmosphere would probably liquify first, there may be oxygen and nitrogen rain with some hail or sleet, but snow? Not sure it would happen.
If it did, ox... |
I discussed the following today.
> 1. If adding an iodine crystal to a Grignard to make the reaction go. will this tiny crystal force some of the metal or reagent to be used
> up. ergo, therefore, there is a lower yield (I know it is microscopic
> change, this is not the question)
It is more about if it takes s... |
I discussed the following today:
> 1. If adding an iodine crystal to a Grignard to make the reaction go. will this tiny crystal force some of the metal or reagent to be used
> up. ergo, therefore, there is a lower yield (I know it is microscopic
> change, this is not the question)
It is more about if it takes s... |
I was wondering about the safety of a specific mineral, Selenite. From my research, I have read that selenite is the crystalline form of gypsum, which is hydrous calcium sulfate. I was wondering if I were to grind selenite and mix about a 1/2 tsp with 3 ounces of water and spray around my home, is that dangerous? Also ... |
Is selenite (hydrous calcium sulfate) dangerous when you grind it up? |
I saw as an example that water is amphoteric (to be more precise amphiprotic), and I came up with the following questions:
Is there any substance that acts as a weak acid and a strong bases at the same time, or vice versa?
If so, or if not so, please give some explanations on the possible reasoning using their st... |
Are all amphoteric substances weak acids and weak bases? |
>Is the total entropy change of all isothermal processes 0?
No. Only for reversible processes.
However your equation is correct.
For an irreversible process in which an ideal gas expands isothermally against a constant external pressure
$$\Delta S_\mathrm{total}=\frac{q_\mathrm{rev}}{T}+\frac{q_\mathrm{surr... |
Consider as solution of pure water at 25 deg C with a kW of 10^-14.
If we are to add an acid to the mix we would observe an increase in hydronium and an equal decrease in hydroxide content.
Yet, I fail to see how the hydroxide ion concentration can decrease with an increase in hydronium concentration.
Lets ad... |
Consider as solution of pure water at $\pu{25 ^\circ{}C}$ with a $k_{\mathrm{W}} = 10^{-14}$.
If we are to add an acid to the mix we would observe an increase in hydronium and an equal decrease in hydroxide content.
Yet, I fail to see how the hydroxide ion concentration can decrease with an increase in hydroniu... |
Consider as solution of pure water at $\pu{25 ^\circ{}C}$ with a $K_{\mathrm{w}} = 10^{-14}$.
If we are to add an acid to the mix we would observe an increase in hydronium and an equal decrease in hydroxide content.
Yet, I fail to see how the hydroxide ion concentration can decrease with an increase in hydroniu... |
>Is the total entropy change of all isothermal processes 0?
No. Only for reversible processes.
However your equation is correct.
For an irreversible process in which an ideal gas expands isothermally against a constant external pressure
$$\Delta S_\mathrm{total}=\frac{q_\mathrm{rev}}{T}+\frac{q_\mathrm{surr... |
In the second episode of [The Association for
Mass Spectrometry & Advances in the Clinical Lab (MSACL)](https://www.msacl.org/) podcast, namely [*Getting going with mass spectrometry : Josh learns chromatography*](https://msacl.simplecast.com/episodes/getting-going-with-mass-spectrometry-josh-learns-chromatography) (a... |
What are the benefits of using zero capillary voltage for discarding fractions in LC–ESI–MS/MS? |
What do they mean by "add 321 g saturated NaCl solution"? Description does not contain volume. |
How to prepared saturated salt solution (NaCl)? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/xB3LJ.jpg
From this reactants I need to draw two products with cyclohexene rings that are enantiomers to each other with chemical formula: C9H14O. And also draw the reaction mechanisms. Why does it form enantiomers? Im not sure how I shoul... |
I was trying to get the line equation for the Pourbaix diagram for the couple $Ni(OH)_2/Ni$. I can write 2 chemical equations. This one in basic conditions:
$$2e^-+Ni(OH)_2\rightarrow Ni+2OH^- $$
Or, this one in acidic conditions:
$$2e^-+Ni(OH)_2+2H^+\rightarrow Ni+2H_2O $$
Now I can determine the line equation for... |
Pourbaix Diagram - Do I have to systematically show the protons in my reaction equation to find the line's equations? |
I have seen electron delocalization mentioned frequently in 2 separate contexts: **resonance**(Ozone, Carbonate/Nitrate...) and **π-conjugation systems** (aromatic compounds).
While the 2 initially sound the same, 2 different points lead me to believe otherwise:
1. π conjugation requires p- orbitals to be in th... |
Suppose we have the following reaction:
$$2\ce{A} \rightleftharpoons \ce{B} + \ce{C}$$
which can be thought the sum of the following reactions:
$$\ce{A} \rightleftharpoons \ce{B}$$
$$\ce{A} \rightleftharpoons \ce{C}$$
with equilibrium constants $K_1$ and $K_2$ repsectively. The $K$ for the first reaction... |
Is it valid to calculate concentrations given equilibrium constant and initial cocnentration? |
Suppose we have the following reaction:
$$\ce{2A <=> B + C}$$
which can be thought the sum of the following reactions:
$$\ce{A <=> B}$$
$$\ce{A <=> C}$$
with equilibrium constants $K_1$ and $K_2$ repsectively. The $K$ for the first reaction will be the product of $K_1$ and $K_2$ i.e. $K=K_1K_2 $. Now if we... |
[![1,3‐butadiene and (3Z)‐pent‐3‐en‐2‐one][1]][1]
From this reactants I need to draw two products with cyclohexene rings that are enantiomers to each other with chemical formula $\ce{C9H14O}.$ And also draw the reaction mechanisms. Why does it form enantiomers? I'm not sure how I should approach this.
[1]: ht... |
Suppose we have the following reaction:
$$\ce{2A <=> B + C}$$
which can be thought the sum of the following reactions:
$$\ce{A <=> B}$$
$$\ce{A <=> C}$$
with equilibrium constants $K_1$ and $K_2$ repsectively. The $K$ for the first reaction will be the product of $K_1$ and $K_2$ i.e. $K=K_1K_2 $. Now if we... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/g927Z.png
In the above HNMR spectrum (400 MHz, CDCl3) the methyl, alkene, and CCl3CH2 protons are fairly easy to assign however, the protons in the hexene ring show overlap and complex splitting (which I assume is due to the axial and equa... |
[![H NMR Spectrum][1]][1]
[1]: https://i.stack.imgur.com/g927Z.png
In the above $\mathrm{^1H \ NMR}$ spectrum ($\pu{400 MHz}$, $\ce{CDCl3}$) the methyl, alkene, and $\ce{CCl3CH2}$ protons are fairly easy to assign however, the protons in the cyclohexene ring show overlap and complex splitting (which I assume ... |
Rare earth and platinum group metals are often found clustered together in the earth's crust. Mining for platinum, for instance, also yields Rhodium and Ruthenium belonging to the same group. Likewise, rare earth elements such as Neodymium, Europium and Samarium also cooccur together in the same ore so much so that the... |
[![H NMR Spectrum][1]][1]
[1]: https://i.stack.imgur.com/g927Z.png
In the above $\mathrm{^1H \ NMR}$ spectrum ($\pu{400 MHz}$, $\ce{CDCl3}$) the methyl, alkene, and $\ce{CCl3CH2}$ protons are fairly easy to assign however, the protons in the cyclohexene ring show overlap and complex splitting (which I assume ... |
Suppose we have the following reaction:
$$\ce{2A <=> B + C}\tag{1}$$
which can be thought the sum of the following reactions:
$$\ce{A <=> B}\tag{2}$$
$$\ce{A <=> C}\tag{3}$$
with equilibrium constants $K_1$ and $K_2$ respectively. The $K$ for the first reaction will be the product of $K_1$ and $K_2$ i.e. $... |
What is the carbon content, by weight, of vegetable oil? |
[![Textbook Explanation][1]][1]Here is what I think I know: The entropy of dissolution reactions increases as methylene groups are added (i.e. butanol has higher entropy of dissolution than propanol). Also, acyclic saturated hydrocarbons become more hydrophobic as the number of methylene groups increases.
Here is w... |
I have seen electron delocalization mentioned frequently in 2 separate contexts: **resonance** (ozone, carbonate / nitrate...) and **π-conjugation systems** (aromatic compounds).
While the 2 initially sound the same, 2 different points lead me to believe otherwise:
1. π conjugation requires p- orbitals to be in... |
Working from the thermodynamic identity;[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/FST03.jpg
Is it allowed to integrate both sides to obtain an expression Ecell= TdeltaS/vF? Assuming deltaS is constant for a reaction and you have Ecell values at some temperatures. Could you plot th... |
Graph of Ecell vs. Temperature giving entropy change/ Fv? |
Working from the thermodynamic identity:
[![The TD equation][1]][1]
[1]: https://i.stack.imgur.com/FST03.jpg
Is it allowed to integrate both sides to obtain an expression $\mathrm{E_\mathrm{cell}} = T \cdot \Delta S/vF$? Assuming $\Delta S$ is constant for a reaction and you have $\mathrm{E_\mathrm{cell}}$... |
Here is the mass spectrum of isobutane:
[![][1]][1]
<sub>(source: [nist.gov](http://webbook.nist.gov/cgi/cbook.cgi?Spec=C75285&Index=0&Type=Mass))</sub>
Clearly the peak at $\mathrm{m/z} = 27$ corresponds to the species $\ce{C2H3+}$, the "protonated acetylene".
I am interested in possible formations for i... |
[![H NMR Spectrum][1]][1]
[1]: https://i.stack.imgur.com/g927Z.png
In the above $\ce{^1H}$ NMR spectrum ($\pu{400 MHz}$, $\ce{CDCl3}$) the methyl, alkene, and $\ce{CCl3CH2}$ protons are fairly easy to assign however, the protons in the cyclohexene ring show overlap and complex splitting (which I assume is due... |
How to assign overlapping multiplets in 1H NMR spectra? |
[![H NMR Spectrum][1]][1]
[1]: https://i.stack.imgur.com/g927Z.png
In the above $\ce{^1H}$ NMR spectrum ($\pu{400 MHz}$, $\ce{CDCl3}$) the methyl, alkene, and $\ce{CCl3CH2}$ protons are fairly easy to assign however, the protons in the cyclohexene ring show overlap and complex splitting (which I assume is due... |
I often carry coins in a cheap plastic sandwich bag. A green solid soon appears. Is it copper oxide? How is the polyvinyl chloride (or polyethylene or polypropylene) greatly accelerating the reaction? Or are they? Are there other chemicals being formed?
Coin collector websites all say vinyl-containing compounds, ... |
I am exploring ways to produce metallic aluminum from lunar regolith. According to most published results of lunar soil, $\ce{ Al2O3}$ comprises roughly 14% of mare samples by mass with $\ce{SiO2}$ being main impurity (40%). From what I been able to understand so far, both Bayer and Serpeck’s processes rely on reagents... |
From Wikipedia:
[![forms of iron oxide][1]][1]
[1]: https://i.stack.imgur.com/Jmlu5.png
What does this graph mean?
What is $lowercase_epsilon$? It looks like epsilon_0, like the vacuum permittivity, but what does this have to do with the polymorph and/or isomers of ferrite or hematite?
... |
What is lowercase-epsilon_0 in this diagram for iron (III) oxide (hematite)? With a (V)? |
I've noticed that some textbooks and video lectures use an amino acid wherein the amino group has two hydrogens, and others use an amino acid with 3 hydrogens in the amino group (in the formation of a peptide bond). How come there are two variations? And also, if the starting amino acid has 3 hydrogens in its amino gro... |
I think there is no perfect answer to this situation. In general when the flow is stopped to any detector in an HPLC experiment, there is a change in baseline, and when the flow is re-started, ghost peaks appear in chromatogram. I am talking about optical detectors such as UV, fluorescence, refractive index etc. Same t... |
I read that the ice sublimes on the moon as the vapour pressure will be really low, but won’t a low vapour pressure increase the boiling point?
(Might be wrong, kindly don’t judge.) |
Ice sublimes on the moon? |
I've noticed that some textbooks and video lectures use an amino acid wherein the amino group has two hydrogens, and others use an amino acid with three hydrogens in the amino group (in the formation of a peptide bond).
How come there are two variations? And also, if the starting amino acid has three hydrogens in it... |
Working from the thermodynamic identity:
$$\Delta{S} = -\Biggl(\frac{\partial{\Delta{G}}}{\partial{T}}\Biggr)_p$$
Is it allowed to integrate both sides to obtain an expression $\mathrm{E_\mathrm{cell}} = T \cdot \Delta S/vF$? Assuming $\Delta S$ is constant for a reaction and you have $\mathrm{E_\mathrm{cell}}$ v... |
Is it valid to calculate concentrations given equilibrium constant and initial concentration? |
How to model CRISPR/Cas9 binding and cleavage using a generalized Kittel's zipper model? |
Lower vapor pressure *lowers* the boiling point. Don't you use a pressure cooker to increase the boiling point of water so that food can cook rapidly?
Why go to the moon? Ice sublimes in Canadian weather, where temperatures can go as low as -40 to -50 Celsius in some cities. People claim that ice sublimes on the roa... |
leaving a spoon in a cup of tap water for about 12 hours makes a pattern of bubbles, why? |
For this cell:
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/kHsSE.jpg
What is the real reason there is no salt bridge? |
Why is there no salt bridge for this cell? |
I have some bottled tea and I noticed that shaking it creates some foamy bubbles that stay for quite a while (at least half an hour if not more). I originally thought it has something to do with my saliva, but then I realized that a brand new bottle of tea also does the same thing. The listed ingredients are water, ool... |
Why do bubbles form when I shake a bottle of tea? |
Why do bubbles form and stay when I shake a bottle of tea? |
Can geometrical isomers(cis-trans, E-Z) interconvert via tunneling ? |
Can Geometrical Isomers interconvert? |
Let's take for example a reaction that would benefit from having less water in it, ester formation from alcohol and acid. We know that the equilibrium can be shifted to the right (ester formation) if water is constantly removed through distillation. My question is: would adding an excess of NaCl affect the reaction and... |
Would adding a water soluble salt (e.g. NaCl) affect a water sensitive reaction? |
Let's take for example a reaction that would benefit from having less water in it, ester formation from alcohol and acid. We know that the equilibrium can be shifted to the right (ester formation) if water is constantly removed through distillation. My question is: would adding an excess of NaCl affect the reaction and... |
Would this be a correct resonance structure? |
Imagine I have 5g vineger which I titrated with 0.1 M Sodium Hydroxide and 33 mL of it (NaOH) has been used in reaction.
I tried V₁S₁ = V₂S₂ formula but It needs the volume of the acid.
I have tried to calculate the volume with W = SVM/1000 formula which gives me 250/3S mL (where S is the molarity of Acetic Acid... |
Can I measure the molarity of Acetic Acid titrating Vineger with Sodium Hydroxide? |
I was trying to get the line equation for the Pourbaix diagram for the couple $\ce{Ni(OH)2}/\ce{Ni}.$ I can write two chemical equations for basic and acidic conditions, respectively:
$$
\begin{align}
\ce{Ni(OH)2 + 2 e- &-> Ni + 2 OH-}\tag{R1}\\
\ce{Ni(OH)2 + 2 H+ + 2e- &-> Ni + 2 H2O}\tag{R2}
\end{align}
$$
... |
Do I have to systematically show the protons in my reaction equation to find the Pourbaix diagram's line equations? |
For this cell:
$$\ce{Pt(s)\vert H2(g)\vert HBr(aq)\vert AgBr(s)\vert Ag(s)}$$
[1]: https://i.stack.imgur.com/kHsSE.jpg
What is the real reason there is no salt bridge? |
From [Wikipedia][2]:
[![Pourbaix Diagram of aqueous Iron][1]][1]
[1]: https://i.stack.imgur.com/Jmlu5.png
What does this graph mean?
What is $\varepsilon$? It looks like $\varepsilon_0$, like the vacuum permittivity, but what does this have to do with the polymorph and/or isomers of ferrite or... |
Imagine I have $\mathrm{5}$ g of vineger which I titrated with $\mathrm{33}$ mL of $\mathrm{0.1 M}$ Sodium Hydroxide ($\ce{NaOH}$).
I tried $V_1S_1 = V_2S_2$ formula but It needs the volume of the acid.
I have tried to calculate the volume with $W = \frac{SVM}{1000}$ formula which gives me $\frac{250}{3S}$ mL (wh... |
For *E1 selection rules* (embodied in the electronic transition moment), to have an allowed transition the direct product of irreducible representations(*IR*) must contain the totally symmetric *IR*.
So for transitions between two $\sum $ states, the following transitions are symmetry allowed $\sum^-↔\sum^- and \sum^... |
Imagine I have 5g vineger which I titrated with 0.1 M Sodium Hydroxide and 33 mL of it (NaOH) has been used in reaction.
I tried V₁S₁ = V₂S₂ formula but It needs the volume of the acid.
I have tried to calculate the volume with W = SVM/1000 formula which gives me 250/3S mL (where S is the molarity of Acetic Acid... |
I had a quick question on virtual libraries. I'm hoping to perform a virtual screen using a library that contains very small, soluble compounds - think glycerol and smaller (<100MW). As far as I can tell, the majority of virtual libraries contain mostly larger, drug-like compounds. Is anyone aware of any libraries that... |
**Please edit the table to include missing data**
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
| Edition | Years(s) | page | value | CODATA? |
|---------|-----------|-------|--------------|-------------------|
| 1 [(Link)](https://books.google.com/books?id=07AHIEp6vYQC&printse... |
Can cis-trans isomers interconvert via tunneling ? |
Can cis-trans isomers interconvert? |
From [Wikipedia][2]:
[![Pourbaix Diagram of aqueous Iron][1]][1]
[1]: https://i.stack.imgur.com/Jmlu5.png
What does this graph mean?
What is $\varepsilon$? It looks like $\varepsilon_0$, like the vacuum permittivity, but what does this have to do with the polymorph and/or isomers of ferrite or... |
What do ε₀ and V mean in a Pourbaix diagram? |
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